1. Field of the Invention
The present invention relates to an electronic package for integrated circuits.
2. Description of Related Art
Integrated circuits (ICs) are typically housed within a ceramic or plastic package. The package has surface pads or leads that are soldered to corresponding pads or holes of a printed circuit board. The printed circuit board may have a number of IC packages and a connector which is plugged into a motherboard. The integrated circuits typically receive power from a power supply that is also plugged into the motherboard.
Electrical noise may exist on the power delivered to the integrated circuit, because, amongst other things, of an impedance mismatch between the printed circuit board and the package. Electrical noise can disturb the operation of the IC. Noise is particularly troublesome for high speed devices such as a microprocessor. The impedance of the printed circuit board can be varied by adding passive capacitors, inductors and resistors to the surface of the board. Mounting additional elements occupies valuable board space and increases both the complexity and cost of producing the board assembly. It would therefore be desirable to provide an electronic package that will reduce the noise of power that is delivered to the package.
Devices which switch at high speeds can create internal inductive effects that disturb the operation of the circuit. Internal IC noise can be reduced by coupling a capacitor to the device. Decoupling capacitors typically have a high capacitance and are relatively large in size. Large capacitors are typically too big to incorporate into the integrated circuit. It would therefore be desirable to provide an electronic package that contains a decoupling capacitor which is connected to the integrated circuit of the package.
Large integrated circuits such as a microprocessor can generate over 20 watts of heat. The thermal impedance of the package must be low enough to ensure that the junction temperatures of the integrated circuit are within safe operating limits. Heat sinks are sometimes incorporated into electronic packages to reduce the thermal impedance of the package. It would be desirable to provide a low cost electronic package which contains a heat sink, a decoupling capacitor for the integrated circuit and means for reducing the noise of power provided to the IC.